It involves forcing boiling water through finely-ground coffee beans under 9-10 bars of pressure. There are a wide variety of coffee beans you can use to make Espresso.
Essentially you put coffee grounds and hot water in the bottom of the press pot, let it sit and then press the top of the device which is a stainless steel filter down to separate the grounds from the water to give you your perfect cup of coffee.
Many coffee aficionados would argue Nespresso does not equate to the ideal cup of Espresso, and they’re right...
All Espressos have a similar quality, but you can’t generalize the flavor because it depends on the coffee varietal you pick, degree of roast, fineness of the granulation, and the skill involved in pulling a perfect shot.
Think of Nespresso as the lite version of Espresso. It’s medium-bodied but rich in flavor and adequate in the aroma department.